3D Si‐on‐Si stack packaging

A new concept of 3D‐electronic packaging is presented: Si‐on‐Si multi‐chip module flip‐chip technology with arrays of fine etched and filled vertical electrical interconnections (vias). Arrays of vias with a high number of interconnections, and not only peripheral interconnections are used. A 3D Si‐on‐Si stack package demonstrator has been realized consisting of four Si‐substrates each representing a system level and containing four thinned and flip‐chip assembled chips. The chips are flip‐chip mounted on the flat side of the Si‐substrates. When interconnecting the Si‐substrates by bump technology the chips submerge into cavities on the rear side of the adjacent Si‐substrate. The chips also test the technology and quality of the electronic packaging, and therefore contain a set of thin film heaters, junctions for temperature measuring, Al‐meanders for stress and strain measuring and daisy chains for conduction path monitoring.